Column at sunlight:
We observe two areas differences.
-Half exposed to sunlight directly have a growth of algae (zone green). In the water see bubbles of oxygen produced by algae, too there are a zone of glucose in the superfice.
-Other half with exposition sunlight indirect there isn't green zone but the black zone caused by the sulfurous precipitated is more expensive.
Column at darkness
There isn't any changes in this column.